FF = GF(next_prime(1000000)) M = Matrix(FF, [[1, 2], [3, 4]]) M.__init__?? reveals that the indices are casted into a long. This might be the problem.
Using Py_ssize_t or size_t might have been a better choice. Jonathan dim...@gmail.com schrieb am Mittwoch, 1. Dezember 2021 um 20:56:16 UTC+1: > > > On Wed, Dec 1, 2021 at 4:39 PM Anton Mellit <mel...@gmail.com> wrote: > > > > When I create a very large matrix (the threshold may be 2^32 entries) > from a list of vectors, the elements are not copied over correctly. > > Here is a "small" example: > > > > FF = GF(next_prime(1000000)) > > M = 70000 > > N = 80000 > > v1 = vector(FF, [FF(k) for k in range(N)]) > > v2 = vector(FF, [N] * N) > > vecs = [v1 + v2*FF(i) for i in range(M)] > > mat = matrix(FF, M, N, vecs) > > mat[0] == vecs[0] > > > > the last line returns "false". > > I understand the bug is not so easy to reproduce: the code above runs > for about 40 minutes and needs about 50G of RAM. In fact, it is also > strange that it takes so long: all the lines until "mat = matrix(FF, M, N, > vecs)" take only about a minute. It shouldn't take so much more time to > simply copy a bunch of vectors than it took to compute them. > > > Matrices in Sage are not just array, they come with parents - vector > spaces of matrices of this size. > Perhaps it's where the time bottleneck is - in creating the parent, that > code wasn't obviously optimised for these kinds of dimensions. > > As to the error... Hard to say, one needs to look at the code (and find a > machine to reproduce the example). > > Dima > > > > Sage version: 9.3 running on a 64 bit linux system > > > > > > -- > > You received this message because you are subscribed to the Google > Groups "sage-devel" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to sage-devel+...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/d06f39c6-f066-4e83-a2c1-2bbcba345f36n%40googlegroups.com > . > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/9c38f81a-f471-41e1-a36f-07b618232f47n%40googlegroups.com.
